The present invention relates to an image display technique intended to display images by irradiating light from light sources onto image display elements and forming an optical image. More particularly, the invention is concerned with a technique intended for displaying bright images.
Known examples of projection image display apparatus include a liquid-crystal projector that irradiates light from a light source onto a liquid-crystal panel such as an image display element, and projects an image in enlarged form on the liquid-crystal panel.
A great number of types of products (projection image display apparatus) applying one or multiple lamps and capable of supplying large electric power to the light source(s) in order to obtain higher luminance have been materialized up to now. Recent trends are that applying light-emitting diodes, organic electroluminescent (EL) elements, or the like, as so-called LED (Light-Emitting Diode) light sources, is being considered for reasons such as their high color purity, excellent longevity, and rapid lighting response. In this case, an LED light unit having a number of arrayed LED light sources is usually used to compensate for the insufficiency of luminance. Examples of the projection image display apparatus that employs such an LED light unit are described in Japanese Patent Laid-Open Nos. 2001-249400 and 2001-343706.